Weight versus Reach

[ReapThaWhirlwind]

When it comes to cranks, would you prefer a lighter crank with a slightly longer crankarm, or a slightly heavier crank with a shorter crankarm?

There tends to be a lot of compromise necessary in the standard market as cranks become obsoleted and only spare versions of them are left at the retail front.

I'm facing one of these issues right now, and would like to hear your input. I personally feel like the shorter crankarm is more important as far as cycling dynamics and drive is concerned over the couple hundred grams you might save, but be forced to reach the extra distance to do so.

[enkei]

AFAIK, crank arm length is critical. Doesn't matter how light the crank is if it's the wrong fit for you. Manufacturers have been woefully inadequate in producing the shorter crank arms needed for many riders, but things are (slowly) improving.

Given that fit is unique to each individual, 'shorter' or 'longer' is immaterial - 'correct' length is what counts.

*I'm no expert.

[ReapThaWhirlwind]

It does matter in some cases, and can have some benefits.

Longer crankarms can provide more leverage. This can mean faster acceleration. And this is at the expense of a little extra stress on the connective tissues to stretch that little bit extra—especially into the onset of deep fatigue.

Shorter crankarms can provide better rotational variable relative to the Q factor. There's less rotation in the revolution for example. This can provide better grinding capabilities and staying power while the bike is in motion.

This is the same principals behind bike tire size and how they affect acceleration and inertia.

Because of all this, the "right fit" can be subjective as there's room to play with. It doesn't truly become the "wrong fit" until it's grossly wrong.

[enkei]

Right but surely, the 'correct' length, however that's defined in your particular application, trumps concerns about weight? Assuming the weight difference isn't measure in kgs....

[Sybian]

My short cranks are lighter than my long cranks.

[Lss555]

(06-15-2023, 11:35 AM)ReapThaWhirlwind Wrote:  It does matter in some cases, and can have some benefits.

Longer crankarms can provide more leverage. This can mean faster acceleration. And this is at the expense of a little extra stress on the connective tissues to stretch that little bit extra—especially into the onset of deep fatigue.

Shorter crankarms can provide better rotational variable relative to the Q factor. There's less rotation in the revolution for example. This can provide better grinding capabilities and staying power while the bike is in motion.

This is the same principals behind bike tire size and how they affect acceleration and inertia.

Because of all this, the "right fit" can be subjective as there's room to play with. It doesn't truly become the "wrong fit" until it's grossly wrong.

Always figured a longer crank would give more leverage but didn’t really think about the fact that if you’re doing like flat road biking a shorter one might be better as you would have less motion and potentially making pedaling marginally easier